Various seat belt systems are shown in prior U.S. patents discussed in detail in the Prior Art Statement filed as part of the present patent application. The primary objective of such prior systems, as well as applicant's system, is to position the shoulder-belt segment for engagement with the upper torso and position the lap belt segment for engagement with the lap of a person when that person enters and sits down in the car. When the door next to that seat is opened, the shoulder and lap segments of the seat belt system are moved to respective positions permitting a person's convenient egress from or entry into the vehicle.